arch: re-order the entries in the float choice

Re-order the three entries in the float choice, in a more sensible
order, ie:
- all hard-float options come first, then soft-float
- options that use the FPU are marked so: hard and softfp
- options that do not use the FPU are marked so: software

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 # Compute Blackfin-specific values

 CT_DoArchTupleValues() {

     # The architecture part of the tuple:

     CT_TARGET_ARCH="bfin"

     # gcc ./configure flags

     CT_ARCH_WITH_ARCH=

     CT_ARCH_WITH_ABI=

     CT_ARCH_WITH_CPU=

     CT_ARCH_WITH_TUNE=

     CT_ARCH_WITH_FPU=

     CT_ARCH_WITH_FLOAT=

 }